Anxiety is a risk factor for the use of opioids and anxiety disorders are highly prevalent among individuals with opioid dependence. Moreover, individuals with co-occurring opioid dependence and anxiety disorders often experience poorer drug use, anxiety, and functional outcomes following treatment. Despite the links between opioid dependence and anxiety disorders and the risk associated with their co-occurrence, very little is known about this common dual diagnosis, and efficacious treatment options have yet to be established. Dr. Rebecca Kathryn McHugh's career goal is to conduct patient-oriented research focused on the co-occurrence of substance dependence and anxiety disorders. The integrated training and research plans proposed in this application will provide Dr. McHugh with advanced training in several critical areas needed to enhance her program of research toward this career goal. Under the mentorship of internationally renowned leaders in the field of substance dependence, training is targeted to the following domains: (1) clinical research in co- occurring disorders (Dr. Roger Weiss), (2) the nature and treatment of opioid dependence (Dr. Weiss), (3) behavioral treatment development and testing (Dr. Shelly Greenfield), (4) the role of stress in substance dependence (Dr. Rajita Sinha), and (5) longitudinal data analytic techniques (Dr. Garrett Fitzmaurice). These training objectives will be achieved through a combination of didactic and applied activities and through the application of these skills in a Stage 1 behavioral treatment development trial involving the development and pilot testing of a novel integrated cognitive behavioral treatment for co-occurring opioid dependence and anxiety (I-CBT). Target areas for learning in each training domain are directly linked to the specific aims of this researc study, which include (1) the development of an integrated cognitive behavioral treatment manual for opioid dependence and anxiety disorders (I-CBT), (2) pilot testing the efficacy of I-CBT for reducing opioid use and anxiety symptoms compared to standard CBT for opioid dependence, (3a) the examination of the association between pre-treatment reactivity to stress and opioid use outcomes following treatment, and (3b) the examination of changes in stress reactivity following treatment. McLean Hospital and Harvard Medical School provide an ideal environment for the attainment of these training and research objectives, including clinical units supportive o patient-oriented research, seminars and courses in designating training areas, and a highly active Clinical and Translational Science Center with a wide array of resources for career development and training. This K23 Award would provide Dr. McHugh with a repertoire of advanced skills designed to complement her prior training and to provide an essential bridge between her prior experience and her career goal to conduct an active program of patient-oriented research as an independent scientist, toward the ultimate goal of reducing the public health burden of substance dependence and anxiety disorders.